1. Field of the Invention
This invention relates, generally, to catheters. More specifically, it relates to open-ended shunt catheter systems with inline filters.
2. Brief Description of the Prior Art
Hydrocephalus is one of the most common pathologies encountered in neurosurgery. On average, 6,000 new babies are born with hydrocephalus every year, including two of every 1,000 babies born in the United States, and thousands of people are diagnosed later in childhood or as adults.
Over $1 billion is spent each year in the U.S. for the treatment of hydrocephalus. The primary treatment of hydrocephalus is cerebrospinal fluid diversion with a ventricular shunt (e.g., ventriculoperitoneal shunts are placed daily in a pediatric neurosurgery practice). In other words, cerebrospinal fluid shunts are positioned to supplement or replace lost drainage capacity. Over 36,000 shunt surgeries are performed each year in the U.S., and over two-thirds are not the first surgery for that particular patient. The total cost of shunts in the U.S. exceeds $2 billion per year, and this does not include the cost of any rehabilitative therapy or educational recommendations. Shunts are life-saving devices but are notorious for high failure rates, difficulty of diagnosing failure, and limited control options. The malfunction rate of these shunts is upward of 40%. The majority of malfunctions occur due to obstruction of the proximal catheter.
Currently catheters are designed as a closed-tube like structure with small drainage holes on the distal end. These drainage holes are small because they prevent large particles from entering the system to possibly obstruct the valve. The problem with this design is that they can be easily obstructed externally by choroid plexus, blood clot, or protein.
Shunts are known and have been described extensively in the art. Examples include U.S. Pat. No. 5,437,626 to Cohen et al.; U.S. Pat. No. 4,741,730 to Dormandy et al.; U.S. Patent App. Pub. No. 2012/0060622 to Harris et al.; U.S. Pat. No. 8,088,091 to Thomas et al.; U.S. Pat. No. 3,690,323 to Wortman et al.; U.S. Pat. No. 4,583,967 to Harris; U.S. Pat. No. 5,531,673 to Helenowski; Reynolds, A. F., P. R. Weinstein, and P. C. Johnson. “Adenocarcinoma Cells Trapped on a Millipore Filter in a Patient with Meningeal Carcinomatosis.” Neurosurgery 7.2 (1980): 179-81; Al-Tamimi, Yahia Z., Priyank Sinha, Paul D. Chumas, Darach Crimmins, James Drake, John. Kestle, Richard Hayward, Guirish A. Solanki, Simon Thomson, and John Thorne. “Ventriculoperitoneal Shunt 30-Day Failure Rate.” Neurosurgery 74.1 (2014): 29-34; Stone, Jonathan J., Corey T. Walker, Maxwell Jacobson, Valerie Phillips, and Howard J. Silberstein. “Revision Rate of Pediatric Ventriculoperitoneal Shunts after 15 Years.” Journal of Neurosurgery: Pediatrics 11.1 (2013): 15-19; Reddy, G. Kesava. “Ventriculoperitoneal Shunt Surgery and the Incidence of Shunt Revision in Adult Patients with Hemorrhage-related Hydrocephalus.” Clinical Neurology and Neurosurgery 114.9 (2012): 1211-216; Chittiboina, Prashant, Helena Pasieka, Ashish Sonig, Papireddy Bollam, Christina Notarianni, Brian K. Willis, and Anil Nanda. “Posthemorrhagic Hydrocephalus and Shunts: What Are the Predictors of Multiple Revision Surgeries?” Journal of Neurosurgery: Pediatrics 11.1 (2013): 37-42; Reddy, G. Kesava, Papireddy Bollam, Runhua Shi, Bharat Guthikonda, and Anil Nanda. “Management of Adult Hydrocephalus with Ventriculoperitoneal Shunts: Long-term Single-Institution Experience.” Neurosurgery 69.4 (2011): 774-81; Reddy, G. Kesava, Papireddy Bollam, and Gloria Caldito. “Long-Term Outcomes of Ventriculoperitoneal Shunt Surgery in Patients with Hydrocephalus.” World Neurosurgery (2013); O'kelly, Cian J., Abhaya V. Kulkarni, Peter C. Austin, David Urbach, and M. Christopher Wallace. “Shunt-dependent Hydrocephalus after Aneurysmal Subarachnoid Hemorrhage: Incidence, Predictors, and Revision Rates.” Journal of Neurosurgery 111.5 (2009): 1029-035; Harris, Carolyn A., and James P. Mcallister. “Does Drainage Hole Size Influence Adhesion on Ventricular Catheters?” Child's Nervous System 27.8 (2011): 1221-232; Thomale, Ulrich W., Henning Hosch, Arend Koch, Matthias Schulz, Giesela Stoltenburg, Ernst-Johannes Haberl, and Christian Sprung. “Perforation Holes in Ventricular Catheters—is Less More?” Child's Nervous System 26.6 (2010): 781-89; Harris, Carolyn A., James H. Resau, Eric A. Hudson, Richard A. West. Candice Moon, and James P. Mcallister. “Mechanical Contributions to Astrocyte Adhesion Using a Novel in Vitro Model of Catheter Obstruction.” Experimental Neurology 222.2 (2010): 204-10; Harris, Carolyn A., and James P. Mcallister. “What We Should Know About the Cellular and Tissue Response Causing Catheter Obstruction in the Treatment of Hydrocephalus.” Neurosurgery (2012): 1; Ventureyra, Enrique C.g., and Michael J. Higgins. “A New Ventricular Catheter for the Prevention and Treatment of Proximal Obstruction in Cerebrospinal Fluid Shunts.” Neurosurgery 34.5 (1994): 924-26; Lin, Julian, Martin Morris, William Olivero, Frederick Boop, and Robert A. Sanford. “Computational and Experimental Study of Proximal Flow in Ventricular Catheters.” Journal of Neurosurgery 99.2 (2003): 426-31; Cheatle, Joseph T., Alexis N. Bowder, Sandeep K. Agrawal, Michael D. Sather, and Leslie C. Hellbusch. “Flow Characteristics of Cerebrospinal Fluid Shunt Tubing.” Journal of Neurosurgery: Pediatrics 9.2 (2012): 191-97; Tal, Michael G., Aldo J. Peixoto, Susan T. Crowley, Neil Denbow, Donna Eliseo, and Jeffrey Pollak. “Comparison of Side Hole versus Non Side Hole High Flow Hemodialysis Catheters.” Hemodialysis International 10.1 (2006): 63-67; Gruber, Rolf W., and Bernd Roehrig. “Prevention of Ventricular Catheter Obstruction and Slit Ventricle Syndrome by the Prophylactic Use of the Integra Antisiphon Device in Shunt Therapy for Pediatric Hypertensive Hydrocephalus: A 25-year Follow-up Study.” Journal of Neurosurgery: Pediatrics 5.1 (2010): 4-16; Takahashi, Yoshihiko, Akira Ohkura, Masaru Hirohata, Takashi Tokutomi, and Minoru Shigemori. “Ultrastructure of Obstructive Tissue in Malfunctioning Ventricular Catheters Without Infection.” Neurologia Medico-chirurgica 38.7 (1998): 399-404; and Jeffrey W. Cozzens et al., Increased risk of distal ventriculoperitoneal shunt obstruction associated with slit valves or distal slits in the peritoneal catheter, Journal of Neurosurgery, November 1997, Vol. 87, No. 5, Pages 682-686. Each of the foregoing references either include or describe the drawbacks of the prior art, namely (1) a closed distal end of the ventricular catheter, (2) ineffective filtering of the cerebrospinal fluid, and/or (3) continued malfunction rates being unacceptably high.
Accordingly, what is needed is a more effective shunt catheter to allow for better flow without occlusion while still maintaining a filtration system to prevent the valve from being obstructed. However, in view of the art considered as a whole at the time the present invention was made, it was not obvious to those of ordinary skill in the field of this invention how the shortcomings of the prior art could be overcome.
All referenced publications are incorporated herein by reference in their entirety. Furthermore, where a definition or use of a term in a reference, which is incorporated by reference herein, is inconsistent or contrary to the definition of that term provided herein, the definition of that term provided herein applies and the definition of that term in the reference does not apply.
While certain aspects of conventional technologies have been discussed to facilitate disclosure of the invention, Applicants in no way disclaim these technical aspects, and it is contemplated that the claimed invention may encompass one or more of the conventional technical aspects discussed herein.
The present invention may address one or more of the problems and deficiencies of the prior art discussed above. However, it is contemplated that the invention may prove useful in addressing other problems and deficiencies in a number of technical areas. Therefore, the claimed invention should not necessarily be construed as limited to addressing any of the particular problems or deficiencies discussed herein.
In this specification, where a document, act or item of knowledge is referred to or discussed, this reference or discussion is not an admission that the document, act or item of knowledge or any combination thereof was at the priority date, publicly available, known to the public, part of common general knowledge, or otherwise constitutes prior art under the applicable statutory provisions; or is known to be relevant to an attempt to solve any problem with which this specification is concerned.